1. Field of the Invention
The present invention relates to a switching element using a phase change film having its resistance varied in accordance with the state of crystal. It also relates to a line-switching device and logic circuit using the switching element.
2. Description of the Related Art
Conventional crossbar circuits used for a field programmable gate array (FPGA) comprise an SRAM formed of six transistors, and a MOSFET as a switching element (see T. Sakamoto, et al., Technical Digest of International Solid State Circuit Conference 2004, No. 1603). When “0” is written to the SRAM, the MOSFET is turned on, while when “1” is written thereto, the MOSFET is turned off. Accordingly, a plurality of lines in an LSI can be dynamically switched by turning on/off the MOSFET.
However, this type of device has the following problem. In the case of a typical FPGA, the crossbar circuits occupy a large area, and a greater part of each crossbar circuit is occupied by the SRAM. Further, the leakage current of the SRAM incorporated in each crossbar circuit is large. In a microfabrication technique of 0.1 μm or less, the leakage current of the transistors is significantly increased in accordance with the development of microfabrication, thereby increasing the power consumption of the entire circuit.
As described above, in the conventional crossbar circuits formed of an SRAM and MOSFET, the SRAM occupies a large area and exhibits a large leakage current.